Immunologic factors related to cancer susceptibility are to be studied in individuals with a high susceptibility to leukemia. A search is to be made for antibodies for agents similar to Australia antigen that could be the causes of diseases related to Australia antigen. Factors related to survival in breast cancer are to be analyzed using clinical data. The chemical composition of Australia antigen from various sources will be determined. The presence of DNA polymerase in human cells in serum will be studied in relation to the propensity to develop cancer.